Heralds of the Siege: The Horus Heresy, Book 52 (Unabridged‪)‬

A galaxy burns and brother turns on brother as the conflict brought about by a beloved son’s betrayal reaches its fateful end. The Warmaster Horus has triumphed. His massive fleet at last nears Terra and the patriarchal Throne of his hated father. Many have fallen to bring this moment about; their tales are the ashes upon which the Heresy was born and prospered. Others have played their own small parts, drops in an ocean of war and blood. 

None of it matters. 

Terra looks to the skies as it raises its defences. Armies muster, heroes raise their swords, citizens cower. The war is coming. And nothing can stop it.